Young monks founded Saint-Feuillien Abbey in the town of Le Roeulx. Before he was canonised, Foillan (as he is known in English) was an Irish monk who came to evangelise in the region, but was murdered there one October evening in 655. Afterwards, many pilgrims came to visit the site of his martyrdom. Every morning, the dew was blood red.

For seven centuries the abbey prospered, not only as a place of prayer and study, but also as a centre of economic, administrative and cultural activity. Between 30 and 40 monks lived there, surrounded by farmers and other tradesmen, including a brewer. In 1796, like many other religious establishments, the abbey was condemned by soldiers of the French Revolution. Saint-Feuillien beer disappeared, but fortunately not for long.